(1) Field of the Invention
The present invention relates generally to radio frequency transmissions from underwater vehicles and, more particularly, an RF transmission signal path created using a plurality of spaced components.
(2) Description of the Prior Art
Deployment of a cable for use in transmitting and/or receiving radio waves from underwater vehicles is known. There are many problems related to use of such cables. However because radio frequency transmissions quickly attenuate in water, specialized cables have been designed for such signals. However, such cables require increased diameters and handling systems that are not practical for many applications.
The following U.S. patents describe various prior art systems that may be related to the above and/or other telemetry systems:
U.S. Pat. No. 5,982,297, issued Nov. 9, 1999, to Welle, discloses a system that includes a first transducer and a second transducer coupled together through a coupling medium communicating input and output undulating pressure waves between the first and second transducers for the transfer of input and output data between an external controller and an embedded sensory and actuating unit. The controller providing input data signals energizing the first transducer and the embedded unit providing output data signals energizing the second transducer collectively for bidirectional communication of data between the controller and embedded unit for functional sensor and actuator process control. The primary advantage of the system is the bidirectional transfer of data through a coupling medium without the use of electrical power wires for controlling embedded sensors and actuators.
U.S. Pat. No. 6,127,942, issued Oct. 3, 2000, to Welle, discloses a system that includes a first transducer and a second transducer coupled together through a coupling medium communicating undulating pressure wave from the first transducer to the second transducer for the transfer of electrical power from an external controller energizing the first transducer transducing the power signal into an undulating pressure wave communicated through the medium to the second transducer traducing the undulating pressure wave into an electrical response signal that can be converted into useful power for powering an embedded sensory and actuation control unit. The primary advantage of the system is the transfer of power through a coupling medium without the use of electrical power wires.
U.S. Pat. No. 6,368,275, issued Apr. 9, 2002, to Sliwa et al, discloses a micro-instrument suitable for property imaging in a body that is less than one millimeter in each dimension. The micro-instrument includes a base having a first wall and a second wall, the second wall substantially circumscribing the first wall, and a lid connected with the base to form a cavity and the lid being temporarily deformable. Optionally, the lid can include a cantilever that is deformable. Also optionally, an electronic circuit can be attached with the micro-instrument. The micro-instrument can also be substantially spherical. An observable property of the micro-instrument varies as a function of a physiological property of the body.
U.S. Pat. No. 6,512,478, issued Jan. 28, 2003, to Chien, discloses an extensible short-range tracking system. The tracking system disclosed is a multi-level tracking system. At the first level is an RF tag, which is a transmit-only unit that transmits information including minimally an identification number. The transmission from the RF tags are sporadic with timing depending upon the application at implementation. Generally, the transmission timing comprises a transmission, which is repeated periodically at random times. Transmissions from the RF tags are received in a series of relays. The relays may calculate the position of the tags by knowing the position of the relays and the time difference of arrival of the signals from the RF tags by several relays or may pass the information needed to calculate position to a base station. Alternately, the RF tags may generate position information and transmit that information along with the RF tag identifier to the relays. The relays, which may be networked among themselves, then relay the information from the tags to a base station unit. The base station unit may be part of various applications such as a fire control system in a military application or an inventory system in an industrial application.
The above cited prior art does not disclose a system for transmitting radio frequency signals through water and perhaps through water to air. The solutions to the above described and/or related problems have been long sought without success. Consequently, those skilled in the art will appreciate the present invention that addresses the above and other problems.